The System: MOBO: Supermicro X9SCM-F CPU: Xeon E3-1230 RAM: 16GB ECC HBA: 1x IBM ServeRAID M1015 (Cross flashed IT Firmware) EXP: 1x Chenbro CK23601 CASE: Norco RPC-4224 HDD: 24 WD Greens (WD20EARX + TLER: 300) PSU: HX850 (Gold efficiency, Single +12v rail) OS: Solaris 11.1 Primary Use: Mass/Bulk Storage (Backups, Media, etc.) The Hardware Config: HBA --> EXP --> RPC-4224 Backplanes --> HDDs. The Drive Config (Desired): 4x 6Disk raidz2 (Separate pools) The Problem: Having just one ZFS pool attached to the system works fine i.e. 6 drives attached. They spin up, scrub, etc work for days/weeks on end with no issues. Adding a second pool i.e. 12 drives attached. pools/drives will work fine as long as they are not both used at the same time. Using BOTH pools at the same time (perhaps transfer data between the two) and drives will start dropping. Usually the same ones, sometimes seemingly random. Adding a third pool is out of the question at this stage. Having just a single pool of 6 drives, and a second pool of a single drive - I can transfer back and forwards between them no problem. (Seems to be an issue with spinning up so many drives at the same time) HBA can get ridiculously hot. Stock/Passive cooling, have a screamer aimed at it though. Looking for opinions/ideas on what to do. ** I'm not going to pretend I'm on expert on this - even if you think there is something glaring obvious, post it; I'd prefer to hear it than have the idea disappear.